Jeremy Corbyn has spoken of being appalled at the response of MPs after the shadow foreign secretary, Hilary Benn, made a fiery speech in favour of the UK joining airstrikes against Islamic State in Syria.

The Labour leader said he did not agree with the rapturous House of Commons response to Benn, whose speech was applauded by the Conservatives and persuaded some of the 67 Labour MPs who backed the military action.

Corbyn, who made the case against airstrikes and carried most of his MPs with him, told the Sunday Times: “I did not agree with it. I was appalled that MPs should clap, shout and cheer when we were deciding to go and bomb somewhere. Parliament is supposed to be serious. It’s not a place for jingoistic cheering.”

He said his critics within the party should share their talents and not obsess about his leadership. Asked about the possibility of a reshuffle in January, he said: “There will be appointments when appointments are made.”

In a slight aimed at some of his colleagues in shadow cabinet, he suggested: “We should hold shadow cabinet meetings in public. I think I’m the only one who doesn’t leak.”

Len McCluskey, the general secretary of the Unite union, which is Labour’s biggest financial backer, said on Sunday that some in the parliamentary party needed to change their attitude, and criticised the small number who have been “enormously disrespectful” towards their leader. He said at the same time Corbyn was “learning to be a leader” and everyone was on a learning curve about the changes in the party.

There has been speculation that the Labour leader will shake up his top team in January – after five months of leadership. Corbyn has had differences of opinion with some in his shadow cabinet not just over the Syria vote but also policy on Trident, which is being reviewed by Maria Eagle, the shadow defence secretary, and Ken Livingstone, the former mayor of London.

On Sunday, Angela Eagle, the shadow business secretary who deputises for him at prime minister’s questions, said she disagreed with Corbyn that the cheering of Benn’s speech on Syria was jingoistic. Eagle, who voted on the same side as Benn, told the Andrew Marr Show on BBC1: “I think it was genuine admiration for the case that had been made by Hilary Benn, which I have to say was far better than the case the prime minister managed to make.

“And can I say at this stage that I think we’re all hopeful that the new UN resolution, which again was passed unanimously, will begin to create a political process to deal with the terrible situation in Syria. I think it’s about time that the world decided it’s got to bring itself to bear to deal with the tragedy going on in Syria.”

Eagle, who is leader of the party’s national policy forum, also sounded cool about Corbyn’s enthusiasm for allowing the membership to have a say on policy. She said Labour needed to allow the public into the process but stressed the important role of the NPF, saying: “We don’t make policy by plebiscite.”